code: def testPeek(self):
      with ops.Graph().as_default() as g:
          with ops.device("/cpu:0"):
              x = array_ops.placeholder(dtypes.int32, name="x")
              pi = array_ops.placeholder(dtypes.int64)
              gi = array_ops.placeholder(dtypes.int64)
              p = array_ops.placeholder(dtypes.int32, name="p")
          with ops.device(test.gpu_device_name()):
              stager = data_flow_ops.MapStagingArea(
                  [
                      dtypes.int32,
                  ],
                  shapes=[[]],
              )
              stage = stager.put(pi, [x], [0])
              peek = stager.peek(gi)
              size = stager.size()
  
      g.finalize()
  
      n = 10
  
      with self.session(graph=g) as sess:
          for i in range(n):
              sess.run(stage, feed_dict={x: i, pi: i})
  
          for i in range(n):
              self.assertEqual(sess.run(peek, feed_dict={gi: i})[0], i)
  
          self.assertEqual(sess.run(size), 10)
  
imports: import queue
  import threading
  import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import data_flow_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 5 for calling the MapStageTest obj's underlying member method code with example usage: obj.testPeek() without return types